Question

What is meant by power of a lens? Write its SI unit. A student uses a lens of focal
length 40 cm and another of -20 cm. Write the nature and power of each lens.
(CBSE 2018)
art is placed at a distance of 15 cm from a concaye lens of focal length 30 cm
(CBSE 2018)
0​

Answer 1

Answer:

power of a lens is its ability to bend a ray of light falling on it and is reciprocal of its focal length. Its unit is dioptre.

Answer 2

Step-by-step explanation:

power of a lens is a measure of the conversions or divergens when lens introduces in the light falling on it.

it's SI unit is dioptre.

lens of focal length 40 cm is convex lens and -20 cm is concave